The invention concerns a force measuring or bending element used in an apparatus for measuring forces.
Such an apparatus comprises a base body (usually metal) to which the bending element is connected. The bending element has a section of reduced thickness which defines a bending region. In response to the application of the force to be measured, the bending element becomes bent at the bending region. By positioning sensing elements, such as strain gauges, at the bending region, the amount of deformation and, hence, the magnitude of the force, can be determined.
Conventional bending elements for a force measuring apparatus have been proposed in numerous configurations, as evidenced for example in German Documents No. 31 48 670 and 32 25 857. The bending elements usually are made of steel, in which connection reference is also made to the bending element disclosed in German Document 27 53 549.
There are numerous requirements for the material from which a bending element is to be formed, such as for example: high hardness and mechanical strength, good workability and weldability, uniform material structure without residual stresses, and the like. The use of a steel material for the bending elements represents a compromise for those requirements. For example, even though steel exhibits good workability and weldability, the bending strength of steel for a given elastic modulus is not very satisfactory. Even the use of special steels, such as those known from aerospace technology, bring only slight improvements, while rendering the structural part significantly more expensive.
A much greater bending strength could be obtained from the use of a ceramic or crystalline material, but those materials exhibit poor workability properties, and it is difficult to obtain a satisfactory connection of such a bending element with the mostly metal base body of the force measuring apparatus.
It is, therefore, an object of the invention to provide a bending element for a force measuring apparatus having an improved ratio of bending strength to modulus of elasticity, and the ability of being joined to the base body of the force measuring apparatus securely and without difficulty.